Provide and use bn_clzw() in place of bn_word_clz().

On some architectures, we can provide an optimised (often single
instruction) count-leading-zero implementation. In order to do this
effectively, provide bn_clzw() as a static inline that can be replaced
by an architecture specific version. The default implementation defers
to the bn_word_clz() function (which may also be architecture specific).

ok tb@

1 files changed, 2 insertions, 2 deletions

diff --git a/src/lib/libcrypto/bn/bn_lib.c b/src/lib/libcrypto/bn/bn_lib.c
index b8eb565497..bac0290efa 100644
--- a/src/lib/libcrypto/bn/bn_lib.c
+++ b/src/lib/libcrypto/bn/bn_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: bn_lib.c,v 1.87 2023/06/21 07:41:55 jsing Exp $ */
+/* $OpenBSD: bn_lib.c,v 1.88 2023/06/21 07:48:41 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -162,7 +162,7 @@ BN_value_one(void)
 int
 BN_num_bits_word(BN_ULONG w)
 {
-        return BN_BITS2 - bn_word_clz(w);
+        return BN_BITS2 - bn_clzw(w);
 }
 
 int